Sen. John McCain of Arizona criticised President Donald Trump’s announcement Wednesday morning that transgender individuals will not be allowed to serve “in any capacity” in the US military.

McCain, who is the chairman of the Senate Armed Services Committee and served in the US Navy for 23 years, said Trump’s statement was “unclear” and it served as “yet another example of why major policy announcements should not be made via Twitter.”

The Republican senator said any Americans who meet the military’s medical and readiness standards should be allowed to continue serving.

“There is no reason to force service members who are able to fight, train, and deploy to leave the military — regardless of their gender identity,” McCain said in the statement. “We should all be guided by the principle that any American who wants to serve our country and is able to meet the standards should have the opportunity to do so — and should be treated as the patriots they are.”

The federal government’s plans for transgender service members and recruits have been up in the air for some time. In June, Defence Secretary James Mattis delayed an Obama administration plan to begin allowing openly transgender recruits into the military by six months.

Mattis said the US Department of Defence needed more time to review the accession plans and potential impact of transgender service members on military lethality. As the review is pending, openly transgender individuals who are currently in the military are allowed to continue serving.

In his statement on Wednesday, McCain said many of those individuals are “serving honorably today.”

“I do not believe that any new policy decision is appropriate until that study is complete and thoroughly reviewed by the Secretary of Defence, our military leadership, and the Congress,” he said.